Gaseous electric discharge device



June 11, H. LEM$ GASEOUS ELECTRIC DISCHARGE DEVICE Filed Aug. 12, 1952 INVENTOR ATTORNEY Patented June ll, 1935 Hendrik Lems, Eindhoven, Netherlands, assignor to General Electric Company, a corpo ation of New York Application August 12,1932, Serial No. 628,578

In Germany August 20, 1931 The present invention relates to gaseous electric'dischars devices generally and more particularly the invention relates to such devices having auxiliary electrodes to facilitate the start-' ding thereof.

A common defect in this type of electric dis-- charge device is that the material of the auxiliary electrodes sputters off during the operation of the device. This sputtered material deposits on the wall of the container to form an opaque coating thereon which reduces the efliciency and the useful operating life of the device.

The object of the present invention is to provide a gaseous electric discharge device having auxiliary electrodes in which sputtering of electrode material does not occur. Another object of the invention is to increase the efliciency and the life of gaseous electric discharge devices of the above type. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description and from the appended claims.

The invention attains its objects by a coating of oxide material on the auxiliary electrodes which prevents the sputtering of material from said auxiliary electrodes to increase the efliciency and the useful operating life of the electric. discharge device.

In the drawing accompanying and forming part of this specification two embodiments of the invention are shown, in which Fig. 1 is a schematic view of one embodiment of the invention and I Fig. 2 is a similar view of another embodiment of the invention.

Referringto Fig. 1 of the drawing the gaseous electric discharge device comprises acontainer I having electrode chambers 2 and electrodes 3 sealed into stems 6 at each end thereof. Said electrodes 3 consist of a coiled metal wire, such as tungsten, coated with an electron emitting material, such as barium oxide, and are adapted to emit electrons when heated. Any other suitable type of thermionic electrode, such as a Pirani electrode, or a Hull electrode, well known in the art,'is used when desired. An auxiliary electrode 4 is sealed into each of said stems 6 and extends toward the center of said'container ,i. Said electrodes 4 are located in the longi- "tudinal axis of said container l and are physically connected to each other in the center of said container l by a body 5 of insulation material, such as porcelain. Said electrodes 5 con- 55 sist of zirconium or aluminum wire and the surface thereof is oxidized. .Where desired electrolytic means are used to oxidize the surface of said auxiliary electrodes 4. g I

Said'container I is filled with a gaseous atmosphere, such as rare gas, common gas, metal va-. por, or a mixture'of these and is, for example, a mixture of argon and mercury at a pressure of approximately 6 to- 8 mm. Where desired, each of said electrodes 4 is connected through an impedance to one of said thermionic electrodes 3, or each of. said electrodes 6 is connected to a sep-- arate current source. I

When cm'rent of 110, 220 or 380 volts is applied to the terminals of the device a discharge takes place between the adjacent end parts of said auxiliary electrodes 4 which ionizes the gaseous filling to facilitate the starting of the positive column discharge in the device. The layer of oxide on said electrodes 4 acts as an insulator and prevents the sputtering of material from said auxiliary electrode 8 during the operation of the electric discharge device.

The embodiment of the invention shown in Fig. 2 is similar to that shown in Fig. 1 except except that cold, cylindrical electrodes 8 and 9 are sealed therein, one at each end-of the container I. A thin metal rod Ill is attached to said electrode 8 and extends along the discharge path between said electrodes 8 and 9 up into the region of thesaid electrode 9. The surface of said rod III is oxidized as disclosed in connection with Fig. -1. When current of 110 or 220 volts is applied to the terminals of the device a discharge takes place between said electrode 9 and the and parts of said auxiliary electrode Ill adjacent thereto which ionizes the gaseous filling to facilitate the starting of the positive column discharge in said device. Due to the coating of oxide material on said electrode It the sputtering of material from said electrode W is entirely prevented.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions,substitutions andchanges in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:-

1. An electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, at least two of said electrodes being main discharge supporting electrodes, an auxiliary electrode extending from one of said said main electrodes, said auxiliary electrode being a zirconium wire coated with zirconium oxide.

3. An electric discharge device comprising a container, electrodes sealed therein, a'gaseous atmosphere therein, at least two of said electrodes being main discharge supporting electrodes, an

auxiliary electrode extending from one ot "said main electrodes to a point adjacent the other of said main electrodes, said auxiliary electrode being an aluminum wire coated with aluminum oxide.

J4. An-electric discharge device comprising a container, a gaseous atmosphere therein, electrodes sealed therein, at least two of said electrodes being main discharge supporting electrodes, two other electrodes being elongated 10 electrodes extending from opposite ends of said container toward the center thereof, the adjacent ends of said elongated electrodes being physically joined by a body of insulationmaterial, each of said elongated electrodes being 15 coated with the oxide of the material constituting said elongated electrode and which is non-sputtering during the operation of the device.

- HENDRIK LEMS. 

